Field of the Invention: The present invention relates to a chemical composition to be added to water, such as in swimming pools, spas, hot tubs, industrial processes, or other water bodies to inhibit, reduce, or prevent the growth of bacteria and/or algae and the formation of common scale minerals in the water.
State of the Art: Many different types of algicides and bacteriacides, also known as treatment agents, have been used to treat water to prevent the growth of algae and bacteria. Use of such treatment agents is especially prevalent in circulating water systems, such as those found in swimming pools, spas, hot tubs, and industrial processes. In addition to preventing the growth of algae and bacteria in water, treatment agents are sometimes used to enhance the aesthetic appeal of the water being treated.
Many recreational water bodies, such as swimming pools, hot tubs, and spas, are susceptible to the formation and growth of algae and bacteria if improperly treated. In addition, the water used to create such water bodies is often hard water, susceptible to scaling, precipitation, and clouding. For example, most swimming pools and hot tubs are filled with tap water drawn from a well or city water supply. Such water typically contains dissolved metals, such as iron, and other impurities, such as calcium carbonate. As water from the water body evaporates, additional tap water is added to replace the lost water. This leads to the concentration of the metals and impurities in the water body. Eventually, the concentration of the metals and impurities results in the formation of scale on surfaces contacting the concentrated water or precipitation of the impurities from the water body. For example, as dissolved calcium carbonate concentrations in a water body are increased by evaporation and refilling, the calcium carbonate begins to precipitate. Calcium carbonate precipitate typically forms as scale on the surfaces holding the water body. Scale formation may be more prevalent on heat transfer surfaces where temperature increases precipitation. The formation of scale, besides being unsightly, is unwanted because it ruins equipment and increases maintenance costs for maintaining controlled water bodies.
To prevent algae blooms, scaling and unwanted precipitation, water bodies are treated. Some of the best-known treatment agents are chlorine and bromine based treatment agents. However, the chlorine and bromine based treatment agents frequently cause skin and eye irritation and are easily recognized by their unpleasant smell. Furthermore, chlorine and bromine react with organic matter in the water to produce foul smelling chloramines and trihalomethanes. In animal toxicological studies with high doses of trihalomethanes an increase in the occurrence of some cancers was observed, which convinced the United States Environmental Protection Agency (EPA) to set limits and regulate human exposure to them. To avoid the irritation and smell of chlorine and bromine based treatment agents, many alternative non-chlorine and non-bromine based treatment agents have been developed. For example, BAQUACIL(copyright), a product of Zeneca, Inc., is a well-known treatment agent used in swimming pools, spas, and hot tubs. BAQUACIL""s(copyright)) unique composition of poly hexamethylenebiguanide (PHMB) provides a substantially irritation free and odorless treatment agent preferable to chlorine for treating swimming pools. Another example of a well-known treatment agent used as the primary ingredient in several commercial products used in swimming pools, spas, and hot tubs is Oxone(copyright), a product by DuPont, Inc. Oxone""s active ingredient is potassium peroxymonosulfate, commonly known as potassium nionopersulfate, an agent also known as a non-chlorine shock. Potassium monopersulfate, like chlorine and bromine is an oxidizing agent that chemically breaks down organic matter in the water, preventing the formation of toxic trihalomethanes.
Many other chemical compositions are also available for treating water. For example, heavy metal ions such as copper, silver, zinc, tin, and nickel have each been used as water treatment agents. The metal ions may be generated in a water supply using electrolysis or by the addition of the metal ion in a solid or liquid form. For example, copper ions are commonly introduced to water as treatment agents in the form of copper sulfate, copper acetate, copper chloride, copper formate, and copper carbonate. One of the problems associated with the use of copper, however, is the tendency of copper ions to react with naturally occurring anions in the water and to precipitate as insoluble salts. To help prevent precipitation, sequestering or chelating agents have been used to enhance the stability of the copper ions in solution. One such chelating agent is ethylene diamine tetra acetic acid (EDTA). The EDTA chelates with the copper ions, or other metal ions, to help prevent precipitation of the metal ion and the staining and scaling caused by such precipitation.
The use of copper ions alone to treat water fails to eliminate undesired calcium carbonate scaling and the precipitation of other metals naturally occurring in water. Although a copper ion source may be combined with EDTA to treat water bodies, problems with precipitation continue to exist. Thus, a treatment agent capable of inhibiting or preventing the formation of algae and bacteria in a water body and also capable of eliminating scaling, controlling the clarity of the water, and controlling the pH of the water is desirable.
The present invention includes a water treatment agent (e.g. composition or mixture) and a method for treating water to inhibit, reduce, or prevent the growth of algae and bacteria, to chemically decompose any organic matter, to inhibit scaling, and to control the pH and clarity of the water.
The treatment agent of the present invention includes copper sulfate penta-hydrate, di-sodium ethylen di-amine tetra-acetric acid dihydrate, a scale inhibitor, and a shocking agent. In addition, a buffering agent may be included in the treatment agent. Scale inhibitors that may be used with the treatment agent of the present invention include 1-hydroxyethylidene-1,1-diphosphonic acid, nitrilo tr(methylene phosphoric)acid, 2-phosphono 1,2,4 butane tri carboxylic acid, H5P3O10, phosphino poly carboxlic acid, poly acrylic acid, and sulfonated poly acrylic acid. Shocking agents may include monopotassium phosphate, potassium monopersulfate, sodium monopersulfate, alkali monopersulfates, and potassium hydrogen peroxymonosulfate sulfate. Buffering agents may include monopotassium phosphate, sulfuric acid, hydrochloric acid, nitric acid, muriatic acid, and oxalic acid.
In a preferred embodiment, the treatment agent includes a chemical composition or mixture including a concentrated solution of about 5 percent by weight of copper sulfate penta-hydrate (CuSO4.5H2O), about zero to about 2.6 percent by weight di-sodium ethylene di-amine tetra-acetic acid dihydrate (Na2EDTA.2H2O), about zero to about 1 percent by weight monopotassium phosphate (KH2PO4), about zero to about 4.3 percent by weight potassium monopersulfate (KHSO5), and about zero to about 1 percent by weight 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP). The treatment agent may be added to a body of water. Ideally, the amount of the treatment agent added to the water body is sufficient to maintain a copper concentration throughout the water body of approximately 1 ppm, and preferably between about zero and about 1.3 ppm. The treatment agent of the present invention may be periodically added to the water body to maintain the desired copper concentration.
In another embodiment of the present invention, the treatment agent may include a chemical composition or mixture comprising a concentrated solution of copper sulfate penta-hydrate, Na2EDTA.2H2O, HEDP, potassium monopersulfate and as much as 15 percent of an acid, such as sulfuric acid (H2SO4). The treatment agent may be added to a body of water on a periodic basis to treat the water body. Preferably, the sulfuric acid is first used to achieve a desired pH in the water body. Periodic additions of the treatment agent may then be used to inhibit the formation of algae and bacteria, prevent scaling, and maintain the pH of the water and the desired water quality.